In the operation of work machines and construction vehicles, quantities of hydraulic oil are used to control various machine operations, functions, and the work implements associated with the machine. Some or all of such hydraulic oil is re-circulated through the machine and components, passing through an oil reservoir tank before being again circulated through the hydraulic circuit.
When such oil is drawn from the oil reservoir tank and passed through the hydraulic circuit to a point of use, and then returned to the reservoir tank for subsequent re-use, varying quantities of air become entrained in the oil. One attempt to remove such entrained air is disclosed in U.S. Pat. No. 2,942,611 wherein oil returning to an oil reservoir tank passes through a common inlet port into an open-ended cylinder which functions as a deaerator. The returning oil is directed into the open-ended cylinder deaerator at a tangent to descend through the cylinder in a swirling motion for facilitating the release of air entrained with the returning oil. The air rises through the open upper end of the cylinder passing into the upper portion of the tank for venting. While such a system may function appropriately for the particular application described, such a deaerator system requires the addition of an extra component, the open-ended cylinder, and does not increase the strength of the tank to dampen any forces of surging liquid during sudden stops.
In U.S. Pat. Nos. 5,564,749 and 4,143,193 there are disclosed hydraulic oil tanks which incorporate structure such as a kiss-off or internal baffles, respectively, which function to increase the strength of the oil tank or container to dampen surges and prevent rupturing. However, neither of the structures disclosed in these patents perform any function relating to the deaeration of air entrained in the oil contained in the containers.
The present invention is directed to overcome one or more of the problems as set forth above.